Figure 2

The phylogenetic tree of the SLC17 family from human (hs, Homo sapiens ), chicken (gg, Gallus gallus ), puffer fish (tn, Tetraodon nigroviridis ), fugu fish (tr, Takifugu rubripes ), zebra fish (dr, Danio rerio ), amphioxus (bf, Branchiostoma floridae ), sea squirt (cs, Ciona savigyni ), fruit fly (dm, Drosophila melanogaster ) and round worm (ce, Caenorhabditis elegans ): Our phylogenetic analysis shows that the SLC17 family consists of four main clades termed III, III and IV with clade I containing two ancient sub-clades. The topology for the tree is calculated from a maximum parsimony (MP) tree and the branch lengths are estimated on that topology using the maximum likelihood method and are proportional to the evolutionary distance. Numbers in boxes indicates MP bootstrap values for the nodes close to the root of the tree. The vGlut family from gnathostomes is removed from the main tree and presented as an insert for clarity although the phylogeny was calculated for the tree including the gnathostome vGluts. Branch lengths for the two trees are drawn using the same scaling.